All-seeing, floating eyes. They can be found in the Castle Corridor area of the Game Boy Advance video game Castlevania: Aria of Sorrow. They creatures are typically employed as spies or sentries.

Trivia

1. Peeping Eye is listed as number seven in the game's monster encyclopedia. They have 38 HP (hit points) and have a base experience point value of 8 points.

2. Acquiring and equipping a Peeping Eye's soul allows Soma to identify weak sections of walls/ceilings/floors that conceal secret areas of the castle (the breakable section will be marked with a vibrating, white circle). If you're going for 100% map completion, you'll find this ability useful in finding rooms you missed. This soul is a 'yellow' type and will automatically become active if you equip it.

3. Generally, these critters are gold/yellow in color in other Castlevania games, instead of the green seen in this incarnation. Also, in other games, sometimes their 'tails' are made out of chain links, rather than spheres.

4. The eye is the only vulnerable point on this creature, striking its tail will get you nowhere. Additionally, there is one Peeping Eye you cannot kill in the game. In one particular hall in the Castle Corridor area, you'll encounter one of these floating orbs spying on you, through the windows, where you can't reach it . . .

5. Unlike many of the other monsters in the game, Peeping Eyes don't have any rare items that you can acquire by defeating them (other than the previously mentioned soul).

ECOLOGY:Peeping Eyes are magical creatures and do not normally inhabit our plane of existance. While alive, they do not perform most of the activities usually associated with life (they do not eat, drink, or breathe, for example). These monsters are generally summoned to this reality by powerful individuals who have need of their special talents (the rites necessary to perform this feat are difficult and known to very few). Although a rare occurrence, it is sometimes possible for a Peeping Eye to stumble into our world, unsummoned, in places where the fabric between dimensions is weak or torn.

ABILITIES:Generally these creatures are placed, by the summoner, in locations where intruders are likely to pass and/or useful intelligence can be obtained. In the absence of such stimuli, Peeping Eyes will lie dormant. In this state they appear as polished spheres lying on the ground (through unknown means, these creatures absorb their tails while at rest). There is no known limit to the amount of time a Peeping Eye can remain like this. Adventurers have stumbled on dormant specimens, covered in inches of dust and cobwebs, that sprang to life as though they had lain for mere minutes, rather than decades. While immobile, Peeping Eyes radiate a short-range, invisible, proximity field; if anything suspicious violates this space, the eye instantly awakens and rises into the air. Although the mechanism is not understood, the sedentary creature can somehow tell the difference between harmless, natural movement (leaves blowing in the wind, rain falling, insects crawling over its surface, etc.) and the undesirable elements it was left to detect. From the moment one of these creatures opens its eye, it magically transmits everything that it sees to its master(s). These images can be viewed mentally, through the 'mind's eye', or watched in various mediums (crystals, mirrors, a pool of water, etc). Receiving these transmissions is voluntary; they can be ignored or 'turned off'. In addition to broadcasting imagery of whatever disturbed it, a Peeping Eye will attack the intruder(s) with its long, undulating tail, which terminates in a sharp barb, unless it was specifically instructed beforehand to only observe. These monsters can perceive many things human eyes cannot, which, aside from earning them their reputation as brilliant watchdogs, makes them invaluable assets in numerous other enterprises, particularly when it comes to locating hidden or invisible objects/phenomena. A Peeping Eye's flight is achieved through magical means and does not appear to fatigue them in anyway. Indeed, they have been observed to remain aloft for days at a time, without rest, when engaged in long-term scouting.

WEAKNESSES:
Peeping Eyes can't take much physical punishment and can be destroyed with relative ease. If its master is observing what the Peeping Eye sees when it is slain, the watcher will often suffer a backlash of energy which can have any number of undesirable effects. If, for example, the creature's keeper was following its movements mentally, the Peeping Eye's death will often cause a sharp pain, followed by a pounding headache, and may even render the master temporarily blind or unconscious. On the other hand, if the cyclopean sentry was observed via some kind of scrying device, it's death will usually result in the breaking or corruption of whatever was being used to watch it (mirrors and crystals will shatter, water will turn to blood, etc). Dormant Peeping Eyes will only 'awaken' if something disturbs their invisible proximity field. If an intruder, whether through luck or skill, stays outside this field, he or she can pass a Peeping Eye safely while it remains inert.